U.S. Pat. Nos. 6,013,318, 5,997,956, 5,863,604, 5,858,465 and 5,652,021 and U.S. patent application Ser. No. 09/067,975 are directed to combustion chemical vapor deposition (CCVD) or controlled atmosphere chemical vapor deposition (CACVD) processes. These processes are open atmosphere, generally atmospheric pressure, deposition techniques. These processes are suitable for coating substrates of almost any size because the substrate need not be confined in a chamber or furnace as is the case in conventional chemical vapor deposition (CVD) processes. In these processes, atomization of chemical precursor solutions is effected by passing the precursor solutions under pressure through narrow diameter needles or nozzles. The teachings of each of the above-identified applications are incorporated herein by reference.
Above-referenced U.S. patent application Ser. No. 09/067,975 describes deposition of certain polymers, such as polytetrafluoroethylene and polyimide, from a CCVD or CACVD flame. These two polymers are relatively heat-stable, although either can be degraded during the combustion process. Herein a CCVD co-deposition technique is used to produce polymer coatings on various substrates, such as glass, silicon, paper, metal, or any other substrate on which a polymer coating would serve a useful function.
A variation of the techniques taught in these patents and applications are used herein to deposit polyimide thin films.